Dawn Candy on tue 30 aug 11
Hello all,
I recently started using ravenscrag slip mixed 80 parts to 20 parts frit =
=3D
3134)=3D20
for a cone 6 clear- based on all that I had read I thought it would be a =
=3D
really=3D20
reliable liner glaze for my functional work. I use it on plainsman M370 =
=3D
clay and=3D20
fire to a pretty hot cone 6. I have noticed that on my goblets the botto=
=3D
m=3D20
inside of the cup will permanently stain with very noticable specks of re=
=3D
d wine=3D20
after one use. Obviously something is wrong with the glaze layer but I'm=
=3D
not=3D20
sure exactly what- I tried applying more and then applying a bit less and=
=3D
all=3D20
the results do the same thing- just the very bottom of the vessel collect=
=3D
s the=3D20
wine and stains. Has anyone encountered something similar? I am wonderi=
=3D
ng=3D20
if I should just scrap it for a new clear even though I like the results =
=3D
where it=3D20
overlaps my other glazes quite a bit.
Dawn
Eric Hansen on thu 1 sep 11
80% Ravenscrag? Is this a glaze for once fired ware or for bisqued ware?
- h a n s e n -
On Tue, Aug 30, 2011 at 7:08 PM, Dawn Candy wrote:
> Hello all,
>
> I recently started using ravenscrag slip mixed 80 parts to 20 parts frit =
=3D
3134)
> for a cone 6 clear- based on all that I had read I thought it would be a =
=3D
really
> reliable liner glaze for my functional work. =3DA0I use it on plainsman M=
37=3D
0 clay and
> fire to a pretty hot cone 6. =3DA0I have noticed that on my goblets the b=
ot=3D
tom
> inside of the cup will permanently stain with very noticable specks of re=
=3D
d wine
> after one use. =3DA0Obviously something is wrong with the glaze layer but=
I=3D
'm not
> sure exactly what- I tried applying more and then applying a bit less and=
=3D
all
> the results do the same thing- just the very bottom of the vessel collect=
=3D
s the
> wine and stains. =3DA0Has anyone encountered something similar? =3DA0I am=
won=3D
dering
> if I should just scrap it for a new clear even though I like the results =
=3D
where it
> overlaps my other glazes quite a bit.
>
> Dawn
>
--=3D20
Eric Alan Hansen
Stonehouse Studio Pottery
Alexandria, Virginia
americanpotter.blogspot.com
thesuddenschool.blogspot.com
hansencookbook.blogspot.com
"Simplify, simplify, simplify" - Thoreau
Ron Roy on thu 1 sep 11
Hi Dawn,
You find the ravenscrag slip analysis for me and I'll tell you how to
make that glaze work as a liner glaze - I'm sure it will be on the
digital fire web site - or ask your supplier.
RR
Quoting Dawn Candy :
> Hello all,
>
> I recently started using ravenscrag slip mixed 80 parts to 20 parts
> frit 3134)
> for a cone 6 clear- based on all that I had read I thought it would
> be a really
> reliable liner glaze for my functional work. I use it on plainsman
> M370 clay and
> fire to a pretty hot cone 6. I have noticed that on my goblets the botto=
m
> inside of the cup will permanently stain with very noticable specks
> of red wine
> after one use. Obviously something is wrong with the glaze layer but I'm=
not
> sure exactly what- I tried applying more and then applying a bit less and=
all
> the results do the same thing- just the very bottom of the vessel
> collects the
> wine and stains. Has anyone encountered something similar? I am wonderi=
ng
> if I should just scrap it for a new clear even though I like the
> results where it
> overlaps my other glazes quite a bit.
>
> Dawn
>
Dawn Candy on fri 2 sep 11
Here is the analysis:
CaO 10.1
K2O 3.0
MgO 1.7
Na2O 0.5
TiO2 0.4
Al2O3 12.7
P2O5 0.0
SiO2 62.1
Fe2O3 0.8
MnO 0.0
LOI 8.7%
I worked with it initially as a simple way to get a non-muddy pale green =
=3D
matte=3D20
using chrome oxide and then decided to try it for a simple hassle-free li=
=3D
ner.=3D20=3D20
M370 can be finicky for glaze fit and the ravenscrag didn't seem to craze=
=3D
at all=3D20
on it. Incidentally, the wine staining does not appear to be the result =
=3D
of any=3D20
crazing- it looks more like a pale purple haze with darker purple specks.=
=3D
=3D20
This is the link for more info about the slip if anyone is interested. T=
=3D
hey have=3D20
some recipes for both cone 6 and 10 there as well.
http://plainsmanclays.com/data/RAVEN.HTM
Dawn
Ron Roy on sat 3 sep 11
Hi Dawn,
Looks like it may need a bit more melt - if you are firing fast the
kiln shelf will hold back the bottom of pots a bit.
This revision will melt a little better - I have kept the expansion the sam=
e.
RAVENSCRAG.................. 75.00
F3134....................... 23.00
SILICA...................... 2.00
=3D=3D=3D=3D=3D=3D=3D=3D=3D
100.00
CaO 0.69* 13.05
MgO 0.10* 1.36
K2O 0.07* 2.40
Na2O 0.14* 2.94
Fe2O3 0.01 0.64
TiO2 0.01 0.32
B2O3 0.24 5.68
Al2O3 0.29 10.19
SiO2 3.11 63.41
Si:Al: 10.57
SiB:Al: 11.39
Thermal Expansion: 453.60
Formula Weight: 294.65
Quoting Dawn Candy :
> Here is the analysis:
>
> CaO 10.1
> K2O 3.0
> MgO 1.7
> Na2O 0.5
> TiO2 0.4
> Al2O3 12.7
> P2O5 0.0
> SiO2 62.1
> Fe2O3 0.8
> MnO 0.0
> LOI 8.7%
>
> I worked with it initially as a simple way to get a non-muddy pale
> green matte
> using chrome oxide and then decided to try it for a simple hassle-free li=
ner.
> M370 can be finicky for glaze fit and the ravenscrag didn't seem to
> craze at all
> on it. Incidentally, the wine staining does not appear to be the
> result of any
> crazing- it looks more like a pale purple haze with darker purple specks.
>
> This is the link for more info about the slip if anyone is
> interested. They have
> some recipes for both cone 6 and 10 there as well.
>
> http://plainsmanclays.com/data/RAVEN.HTM
>
> Dawn
>
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